Method for restoring heavy metal contaminated soil through cooperation of magnetic activated carbon and activating agent

Abstract

The invention discloses a method for restoring heavy metal contaminated soil through cooperation of magnetic activated carbon and an activating agent. The method includes the following steps that firstly, the activating agent is added to the heavy metal contaminated soil, and the soil is tilled evenly and activated for 20 d to 30 d; secondly, the magnetic activated carbon is added to the activated heavy metal contaminated soil, and the soil is tilled evenly and adsorbed for 20 d to 30 d; thirdly, the magnetic activated carbon is recycled in a magnetic separation manner; fourthly, the magnetic activated carbon recycled in the third step is soaked in 0.1 mol / L to 0.5 mol / L of acid liquid for 1 h to 2 h and washed through deionized water to be neutral so as to be recycled; fifthly, heavy metal ions in the acid liquid for washing the magnetic activated carbon in the fourth step are recycled; and sixthly, the first step to the fifth step are cycled till the content of heavy metal in the soil reaches the standard. After the method is adopted for cyclically restoring the soil at three times, the content of heavy metal in the heavy metal contaminated soil can reach the secondary standard, and the method is simple, efficient and short in period.

Description

technical field [0001] The invention relates to the field of contaminated soil treatment, in particular to a method for repairing heavy metal-contaminated soil with magnetic activated carbon and an activator. Background technique [0002] my country's existing heavy metal polluted cultivated land is about 300 million mu, most of which have not been properly treated, and with the rapid development of industry and agriculture, the discharge of waste generated by mining, smelting, electroplating, chemical and other industries, as well as irrigation, pesticides and fertilizers The irrational use of metals is also exacerbating the pollution of heavy metals in the soil. [0003] In the prior art, there are mainly two ways to control soil heavy metal pollution. One is to change the existing state of heavy metals in the soil and reduce their mobility and bioavailability in the environment, including deep tillage, soil dumping and amendments. Among them, the deep tillage method will ...

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Problems solved by technology

[0002] my country's existing heavy metal polluted cultivated land is about 300 million mu, most of which have not been properly treated, and with the rapid development of industry and agriculture, the discharge of waste generated by mining, smelting, electroplating, chemical and other industries, as well as irrigation, pesticides and fertilizers The irrational use of metals is also exacerbating the pollution of heavy metals in the soil

[0003] In the prior art, there are mainly two ways to control soil heavy metal pollution. One is to change the existing state of heavy metals in the soil and reduce their mobility and bioavailability in the environment, including deep tillage, soil dumping and amendments. Among them, the deep tillage method will lead to the diffusion of pollutants in the surface soil, and the heavy metals may be activated in the deep soil; although the soil discharge method will greatly reduce the content of heavy metals, it will also cause the loss of fertile soil on the surface and excavation. The resulting soil is difficult to post-process and other issues; the use of amendments can only temporarily fix heavy metals in the soil, reducing heavy metals entering the human body through plants, but cannot completely remove heavy metals from the soil, and there are still hidden dangers

Another method is to remove heavy metals from soil. The methods for removing heavy metals from soil include chemical leaching and phytoremediation. Chemical leaching can reduce the availability of heavy metals to plants, but at the same time it will cause a large amount of loss in the soil. At the same time, the method of chemical washing may also lead to acidification or alkalization of the soil; and the method of phytoremediation is to remove heavy metals from the soil through the absorption, accumulation and volatilization of plant systems to reduce heavy metal pollution , the cost of this method is relatively low, and it is green and environmentally friendly, but the adsorption of heavy metals by plants has a saturated amount, and the cycle of phytoremediation is relatively long, and the recovery of heavy metals is also a big problem

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